LOCATION STANDLEY CO+UTEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Aridic Argiustolls
TYPICAL PEDON: Standley gravelly clay loam - nonirrigated cropland. (Colors are for dry soil unless otherwise noted.)
Ap1--0 to 5 inches; dark grayish brown (10YR 4/2) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, friable, sticky; 15 percent pebbles; mildly alkaline; abrupt smooth boundary. (2 to 7 inches thick)
Ap2--5 to 9 inches; dark grayish brown (10YR 4/2) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; hard, friable, sticky; 15 percent pebbles; mildly alkaline; abrupt smooth boundary. (2 to 6 inches thick)
B2t--9 to 17 inches; brown (10YR 5/3) gravelly clay, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; very hard, firm, very sticky; 15 percent pebbles; mildly alkaline; clear smooth boundary. (6 to 10 inches thick)
B3ca--17 to 22 inches; pale brown (10YR 6/3) gravelly clay loam, brown to dark brown (10YR 4/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; hard, friable, sticky; 15 percent pebbles; lime occurs as coatings on pebbles and disseminated throughout horizon; strongly effervescent; moderately alkaline; clear wavy boundary. (3 to 8 inches thick)
C1ca--22 to 37 inches; very pale brown (10YR 8/3) gravelly clay loam, very pale brown (10YR 7/4) moist; massive; slightly hard, very friable, sticky; 15 percent pebbles; disseminated lime with thick coating on pebbles; violently effervescent; moderately alkaline; gradual wavy boundary. (12 to 18 inches thick)
C2ca--37 to 60 inches; very pale brown (10YR 8/3) gravelly loam, very pale brown (10YR 7/4) moist; massive; slightly hard, very friable, sticky; 25 percent pebbles; disseminated lime with thick coatings on pebbles; violently effervescent; moderately alkaline.
TYPE LOCATION: Jefferson County, Colorado. Approximately 1/2 mile north of Standley Lake; 80 feet west and 415 feet north of the southwest corner of the northwest quarter of Sec. 16, T. 2 S., R. 69 W.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 15 to 30 inches. Depth to calcareous material ranges from 5 to 20 inches. Rock fragments range from 15 to 35 percent by volume in the solum and are mainly 1/8 to 3 inches in diameter but include 3 to 10 inch in diameter fragments. Coarse fragments are rounded. Calcium carbonate equivalent in the B3ca and Cca ranges from 5 to 25 percent. Mean annual soil temperature ranges from 47 to 52 degrees F.
The A horizon has hue of 10YR or 2.5Y, value of 3 through 5, 2 or 3 moist, and chroma of 2 or 3. Reaction is neutral or mildly alkaline. Textures are modified with gravel, cobble and/or stone coarse fragments.
The B2t horizon has hue of 10YR or 2.5Y, value of 4 through 6, 3 or 4 moist and chroma of 2 or 3. Reaction is neutral through moderately alkaline. It is gravelly clay loam or gravelly clay. Clay content ranges from 35 to 50 percent.
The C horizon, has hue of 7.5YR through 2.5Y, value of 5 through 8, 4 through 7 moist and chroma of 3 through 6. It is gravelly loam, gravelly clay loam, gravelly sandy clay loam or cobbly sandy clay loam.
COMPETING SERIES: These are the Ashfork, Blackpipe, Boneek, Boquillas, Chapin, Collbran, Emigrant, Huggins, Kube, Leyden, Loma, Nunn, Querc, Rednunn, Richfield, Ryus, Savo, Showlow, Sofia, Thunderbird, Torreon and Wormser series. Ashfork, Blackpipe, Boquillas, Chapin, Emigrant, Huggins, Leyden, Querc, Thunderbird and Wormser soils have bedrock within depths of 40 inches. Boneek, Collbran, Kube, Loma, Nunn, Rednunn, Richfield, Ryus, Savo and Sofia soils have less than 15 percent coarse fragments in the solum. Showlow soils have hues of 7.5YR and redder in the B2t horizon. Torreon soils have sola over 40 inches thick.
GEOGRAPHIC SETTING: Standley soils are on terraces, alluvial fans, convex ridges, and valley side slopes and have slopes of 0 to 70 percent. Elevations range from 4,000 to 6,500 feet. The soils formed in calcareous mixed gravelly and cobbly alluvium. The soils are in a semi-arid climate with annual precipitation ranging from 13 to 17 inches. The mean annual temperature is 47 to 52 degrees F. The frost-free season is 125 to 145 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Leyden and Nunn soils and the Denver, Kutch, and Midway soils. Denver and Kutch soils have less than 15 percent coarse fragments in their profiles. Midway soils have bedrock at depths of less than 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Soils are used for grazing, nonirrigated and irrigated cropland and community development. Native vegetation is blue grama, little bluestem, sideoats grama, needleandthread, western wheatgrass, forbs, and shrubs.
DISTRIBUTION AND EXTENT: Foothills and plains area of eastern Colorado. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Golden Area Soil Survey, Jefferson County, Colorado, 1980.
REMARKS: Last updated by the state 4/80.